The Effects of Too Much CO2 In a Grow Room


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A grow room, also known as a growth chamber, indoor garden, indoor farm, or sometimes a plant factory, is a specialized room, located indoors, to allow plants to grow under controlled conditions. 

They are great for people who are restricted from growing plants outside – not everyone has the luxury of a garden in their home!

If you are a keen grow room grower, you need to understand gaseous exchanges that occur and what happens when levels get out of control. 

Too much CO2 in a confined area such as a grow room, poses serious threats to human health, sometimes leading to death. We are here to tell you why and what you can do to prevent such issues from occurring.

CO2 Levels: Good for Growing & the Dangers of Too Much

CO2, carbon dioxide is an inert gas that is colorless that naturally occurs in the atmosphere. Plants require CO2 for both photosynthesis and respiration, which is why this molecule plays a vital role in promoting and enhancing your plant yield. 

Indoor plant growers that utilize grow rooms require CO2 as a key component to successfully grow plants. Much like baking a cake, plants also require a recipe to perform photosynthesis. In this case, the ingredients to a “growth recipe” are water (H2O), light, and of course, the topic today, CO2. 

Photosynthesis is an important process that converts light energy into chemical energy via cellular respiration. It is this process that fuels metabolic activities within plants. 

Too much CO2 can be a problem, and this is not only an issue for your plants in a grow room, it also has negative effects for you. As mentioned, plants need CO2 to live, but give them too much and the vital nutrients they produce, become depleted. These include iron, zinc, and vitamin C. Signs of too much CO2 in plants are thickened leaves. 

Now onto you… 

Many indoor plant growers are unaware of the potential hazard of elevated levels of CO2 in a confined area, which is what a grow room is. A grow room works wonders as it traps everything inside, controlling the area for your plants, but dangerous levels of CO2 can lead to serious health problems for humans.

When CO2 levels climb to 5,000 ppm problems such as toxicity or oxygen deprivation can occur which is more exposure than we are used to. We start to feel disorientated from dizziness, can become unconscious, and elevated CO2 levels can even be fatal.   

Why is CO2 Used to Grow Plants, in Particular Grow Rooms?

There is a long history of using CO2 generators in greenhouses and grow rooms. These generators burn fossil fuels to generate CO2. Studies have found that when CO2 concentrations are increased between 200 and 400%  of the natural concentration, it encourages plant yields to grow at a much faster rate. 

When plants grow at a higher yield, productivity is more efficient resulting in a better quality crop. 

Plant growers have moved on from CO2 generators to CO2 enrichment. With climate change a major issue today, and the burning of fossil fuels often leaving residue in the plants, using CO2 enrichment is more popular and much easier to control. 

What to Know Before Using CO2 in a Grow Room

Before you introduce CO2 into a grow room, it is important to understand how. 

There are three main ways:

  • Via a regulated tank of CO2
  • Via a natural source of CO2
  • Via propane or natural gas burners

Regulated CO2 Tank

Most hydroponic stores will sell canned CO2, so it is readily available, but ensure you have a CO2 regulator set up to create a constant flow of CO2 outside the tank. 

They are simple to use, making them extremely popular with grow room enthusiasts. Simply set the desired flow of CO2 and set the timer. This will require you to calculate the required CO2 levels. 

If you do not feel confident calculating the CO2 levels, you can purchase a CO2 PPM controller. 

Regulated tanks are perfect for larger grow rooms, as you can walk around the room with ‘CO2 on tap’, manually (or semi-manually) supplying your plants with CO2.

If you are extremely concerned with safety, they are also much safer to use than CO2 generators and burners.  

Natural CO2 Source

These work best in smaller grow rooms. The device is placed above the plants and CO2 is naturally released.  

However, the coverage of this CO2 source is pretty low, so they are best for supplying CO2 to the plants directly below the device. Saying that, if you do prefer this input of CO2, then you can stock up on multiple devices to get a larger coverage. 

Propane/Natural Gas Burners

These are usually used in grow rooms that exceed 10ft x 10ft. Burners aim to produce minimal heat and produce as much CO2 as they can. 

These specialized CO2 generators use either natural gas or liquid propane that create a combustion reaction with CO2 and H2O (and heat) being byproducts. H2O levels come from humidity, so keep a close eye on this when growing your plants. Luckily for you, we have a high-quality humidity sensor that we use in our labs. 

Sometimes CO2 generators can release toxic carbon monoxide if the fuel is not burned properly. Most CO2 monitors will exhibit a red flame to show you there is a problem. 

NOTE: CO2 capacity is measured in cubic feet per hour (CFH). Smaller grow rooms are not able to utilize high CO2 levels, so you will need to make adjustments such as lowering the PPM. 

CO2 Safety

As the use of CO2 at high levels can be an issue for human health, you must consider the safety aspects when using a grow room. 

Any sealed and secure room poses potential safety hazards for growers like yourself. Any leak in the CO2 enrichment system is a huge problem. 

When CO2 is released in a room, it settles on the floor, due to CO2 being heavier than oxygen. The CO2 will then rise until the whole room is filled, depleting oxygen levels in the room potentially causing serious health concerns such as CO2 poisoning, unconsciousness, or even death. We highly recommend a CO2 monitoring device to check the CO2 levels, with some states implementing one as a requirement for particular grow rooms. 

Even small CO2 leaks should not be overlooked. These can quickly build up to become fatal. If you suspect a leak, always turn off the system (if you can) and call a fire marshal and inspector to check out the system immediately before proceeding with growing. 

How to Measure and Modulate CO2 In a Grow Room

We highly recommend using CO2 tanks with a CO2 regulator – these will release a certain amount into the room with a timer. This reduces the chances of something going terribly wrong. 

Because CO2 is difficult to detect, at Atlas, we have a CO2 sensor that is a compact Non-Dispersive Infrared sensor helping you to read CO2 levels (in ppm). With the ability to read CO2 levels of 0-10,000ppm, you will never reach that toxic level!

How Much CO2 Should You Add to Your Grow Room?

Using our sensor, you can regulate the amount of CO2 in your grow room. You can calculate how much CO2 needs to be released in your grow room by determining the volume of your room: length x width x height. 

Once you have the grow room volume, you need to multiply by the amount of CO2. For example, if your CO2 level is 0.2% (2000 ppm), you would multiply the room volume by 0.002 (0.2%). 

To calculate how long the valve should be open, you need to divide the hourly flow rate by the number of cubic feet of gas required. 

If this sounds too technical, there are many online CO2 calculators for grow rooms. 

Summing Up CO2, Testing Equipment and Advice

The effects of too much CO2 in grow rooms should be something you are now more aware of. 

Your grow room aims to grow a good yield of plants right?  Well, give them too much and the vital nutrients they produce, become depleted. Also, remember that CO2 leaks can be fatal to humans, so maintaining your grow room and being fully equipped is essential. 

At Atlas Scientific, we understand how important your investment is to you. By gearing up with our CO2 sensor, you will be able to invest more time into growing, and less time worrying about dangerous levels of CO2!

We look forward to answering all your questions and helping you on your journey. Feel free to reach out to one of our staff at Atlas Scientific, part of our world-class team. 

Thank you for reading, we hope to see you again soon, happy growing!

CO2 Sensor & Scrubber

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